Try the following steps to see if they help:

1. Switch between various projection modes to see if your projector can play sound.

2. Press the Volume Up button on your projector remote .

3. In Projection Mode, connect your projector to an external Bluetooth speaker by going to Settings > Display and Sound > Sound > Turn On Bluetooth Speaker Mode.

If the above solutions cannot solve your issue, please contact Nebula Customer Support at support@seenebula.com for further assistance.